Airliner crash

newbiesim · Guest

I just read the news story of this tragedy and was struck by some of the details reported.

Apparently the 737 suffered rapid depressurization at 30000 ft. Fighter jets scrambled and the F-16 pilots reported the pilot slumped down in his seat and oxygen masks dangling.

The Pilots also saw a person apparently trying to assume control of the 737, either another crewman or passenger. At that point the airliner was flying on autopilot.

As a newcomer to flight sims, I am struck with the "art imitating life " aspect of it. The sims are quite realistic and judging from my few hours of flying around in some real cessnas, a competent sim pilot and a competent real pilot are not seperated all that much in terms of skill. Obviously the stakes are higher and the real pilot has real physics to deal with, but really, I suspect a long time sim pilot would be right at home in a real cessna and probably breeze thru flight training because the actual manual skill of flying the aircraft is not all that hard and much of real flight training, all the procedures and such are duplicated in the sim.

Taking this to the extreme, and given the large number of sim pilots out there and the popularity of the big airliner segment of the hobby, and in light of this recent tragedy, I started wondering. Perhaps the real pilots and sim pilots here that are familiar with the 737 could give their opinions.

I hope this post is not in poor taste, but I was struck by the heroic efforts of the person who apparently attempted to regain control of the aircraft.

Given what is suggested by the evidence so far, such a rapid decompression at 30000 ft would incapacitate passengers and crew alike quite quickly, maybe around 15 seconds from lack of oxygen. The passengers final text messages reflected the dangerous low cabin temperature as well, but Im sure the lack of oxygen would be the immediate danger.

So my first question is are the oxygen masks deployed automatically when depressurization occurs? I would assume the crew members are trained to know they have to get those masks on in a hurry. Surely you could strap the mask on in a few seconds, or perhaps the rapid loss of pressure has other incapacitating effects ?

At any rate Im wondering the chances of say, one of the sim pilots here who fly 737s could have realized the emergency, took a few breaths from his oxygen mask, and actually made it into the cockpit and then safely do an emergency descent?? Assume the cabin door to be open (improbable these days for sure).

How long would it take to lose 20000 ft safely? Would it then be possible to turn on the autopilot and attempt to revive the pilot? Could a single sim pilot pull off the approach and emergency landing without the crews assistance? Would hypothermia set in ? Are the flight indtruments and avionics and such designed to function under extreme low cabin temps?

This same type of failure took down a lear jet not so long ago. This scenario is certainly possible albeit unlikely so maybe its worth discussing the options such an emergency might present, IMO. Im not trying to trivialize the tradgedy to the level of a hollywood disaster movie or anything. From what I know (not much!) I think a competent sim pilot and some lucky conditions might just be a viable last resort.

Guest · Posted: Mon Aug 15, 2005 2:36 am Post subject:

A well written post...

I heard that at that kind of altitude, any breath in your lungs would be forced out due to the cabin pressure - so i dont think you could take a few breaths of your oxygen mask and walk off....

Chris102 · Chief Captain Joined: Oct 09, 2004 Posts: 1237

Very sad

Av8r77 · Posted: Mon Aug 15, 2005 3:45 am Post subject:

A rapid decompression will caue a "cloud" to form in the cabin. This is caused by the rapid temperature change. The masks are supposed to drop down (I beleive) anytime to altitude exceeds 10,000M.

At 30,000 feet, you could last 1-2 minutes. After that, you would be rendered unconcious from hypoxia.

As far as a sim pilot being able to land the plane, it's highly unlikely. The sim is good training, but dealing with an actual 737 is something entirely different. I would say 1 out of 100 would land it.

An emergency descent could have taken place, and depending on the gross weight of the aircraft, can be done at about 3,000-4,000 fpm. You would be "floating" in your seat, but the point is to get below 10,000 to survive.
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newbiesim · Guest

Thanks for the replies. I gather this must have been a rapid depressurising event indeed. Perhaps it would be like an explosion,in reverse, and such a shock to the body as to immediately incapacitate. I was curious about the oxygen masks apparently not being put on.

Perhaps the loss of pressure was more sudden in the cockpit and immediatly incapacitated the crew or perhaps one member of the crew had a better tolerance to the effects, because of the report of someone in the cabin moving about?

Are there not redundant systems for this sort of emergency? It would seem critical to at least protect the cabin from such rapid loss. Since I assume they keep the cabin door shut(for security), some sort of emergency system besides the oxygen masks, which might be useless to an incapacitated crewman, would seem to be in order. Of course, if metal fatigue caused a rupture of the skin of the airframe there would be nothing to prevent the rapid loss of air.

As far as landing, arent there automated systems for bad weather?

Forgive my newbie questions,but I never really worried about depressurisation that much before. I figured no big deal,just put on the O2 mask like the attendant demonstrates, and the pilot just dives for safer altitude. Might get to use the barf bags, and certainly a bit more excitement but nothing to bring down a modern jetliner.

But now I know a lot of your safety at altitude is dependent on keeping the aircraft pressurised and the thin sheet aluminum wrapping the fuselage. But I wont hesitate to fly.

newbiesim · Guest

I now gather that it may have been actually a very slow loss of pressure that would cause everyone to pass out. I can see how this could happen, but I would hope the airliners would have something go beep real loud or otherwise give warning before O2 levels dropped too low for rational action.

Surely with all the high tech equipment some automatic alarm would be in place? As far as the A/C never pressurising, Dosent the flight engineer monitor such things ? Isnt checking for pressurisation part of some checklist? As fast as jets ascend,wouldnt the cabin pressure guage sink fairly rapidly and be an obvious indicator to cease climbing?

Av8r77 · Posted: Mon Aug 15, 2005 7:43 am Post subject:

Slow depressurzations are deadly.

Something known as Hypoxia sets in. Your body isn't getting oxygen in it's bloodstream, and thus the brain isn't getting what it needs. You start having symptoms of euphoria, where you really don't know that anything is wrong. Your finger nails and lips may turn blue and you have problems performing the simplest of tasks, like 4th grade math.

As the aircraft is ascending, the pilot not flying will pressurize the aircraft using the bleed air. If there is a slow leak in this system there is no warning of it. Some aircraft have a pressurization warning, but it's usually only a light that illuminates. If you aren't in the frame of mind to see it, you'd never notice such things in that state.

A rapid decompression does not render someone incapacitated in a matter of seconds. I was at 24,000 feet a few months ago and we had a Rapid-D. Once we all recognized it, from the cloud of mist in the cockpit, and reached for our helmets and oxygen masks, it was a good 30-40 seconds. Nobody passed out, and we declared the emergency and descended below 10,000.

I am willing to bet what happened to this crew and passengers was a slow, unnoticable loss of pressure that all of them literally fell asleep from the lack of oxygen.
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ThomPilot · Trainee Joined: May 27, 2005 Posts: 1

ueah i also guess it was a slow losing of oxygen in the flight cabin and maby in the passengers cabin... sad.. Sad

tomthetank · Posted: Mon Aug 15, 2005 6:08 pm Post subject:

If it was a sudden loss of pressure it would take you by suprise and you would have no time to take any deep breaths.

The two black boxes have been recovered,lets all hope that they find out what caused this tragic event quickly.

Amen
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Av8r77 · Posted: Mon Aug 15, 2005 8:13 pm Post subject:

Hold your breath for 40 seconds. Even with a rapid decompression, you have time to react. Their is still Oxygen in the air at 30,000 ft, just not enough for your body to function off of. You can still respirate.
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